Blade holding means for hacksaws and the like



y 1939. D. E. PRIEST El AL 2,166,446

BLADE HOLDING MEANS FC JR HACKSAWS AND THE LIKE Filed Feb. 5, 1957 (PmozART) lZM'g/Zf E3 Priest Egg/"y Fffacwnfi'er Patented July 18, 1939UNITED STATES PATENT OFFICE BLADE HOLDING MEANS FOR HACKSAWS AND THELIKE Application February 5, 1937, Serial No. 124,278

1 Claim.

The present invention relates to the construction and manufacture of thedevices which are associated with a hack saw frame and which serve forthe holding and tensioning in said frame of the saw blade. Our inventionprovides a onepiece blade retaining device which affords a maximum widthof bearing surface for the end of the blade and, at the same time, isreadily insertable in the squared socket or other receiving meanstherefor provided by the end of the hack saw frame; our inventioncontemplates the manufacture of such retaining devices from headed boltsor rivets of substantially conventional type. Other and further objectsand advantages of the invention will be made apparent in the followingdetailed description thereof, reference being had in this connection tothe accompanying drawing, wherein Fig. 1 is a perspective view of one ofthe headed bolts or rivets, of substantially standard form, used in themanufacture of my improved retaining device.

Fig. 2 is a perspective View illustrating the usual blade-retainingdevice as made from the bolt or rivet of Fig. 1.

Fig, 3 is a perspective view, illustrating the results of upsetting anddrawing operations performed on the bolt or rivet of Fig. 1, to providethe retaining device of our invention.

Fig. 4 is a similar view of the blade retaining device shown by Fig. 3,as seen from the other side.

Fig. 5 is a fragmentary view illustrating a portion of a hack saw frame,with the device of Fig. 3 used therein.

Fig. 6 is a fragmentary large scale view illustrating the act ofinserting our improved retaining device in said frame.

Like reference characters refer to like parts in the different figures.

Referring first to Fig. 1, there is shown a substantially conventionalbolt or rivet having a head I and a shank 2, as the stock from which ourimproved blade-retaining device is fashioned.

One step in the manufacture of this bolt or rivet, forming no part ofour present invention, is the formation on shank 2, immediately adjacentthe underside of head I, of a squared section 3 which, as hereinafterdescribed, is matched by a square aperture or socket of the hack sawframe. In the ordinary manufacture of a blade-retaining device from thebolt or rivet of Fig. 1, the latters shank 2 is slabbed or flattened offas shown at 4,

Fig. 2, substantially on a diameter of said shank and in a plane thatsubstantially bisects the squared section 3 and parallels two oppositesides of the latter. A pin 5, driven into the material of shank 2,projects outwardly from the slabbedoff surface 4 and is adapted, in theusual manner, to be detachably engaged by a hole formed in one end ofthe saw blade, the latter, when engaged with pin 5, bearing flatwise atsaid end against the flat or slabbed-off'surface 4 of the retainingdevice, as shown by the broken lines in Fig. 2.

With this conventional blade-retaining device shown by Fig. 2, thebearing surface 4 is so limited in width that it affords very littleresistance to tipping or turning of the blade, when the saw is in use.In such cases where a greater width of bearing surface was desired, ithas been the practice (see Fig. 1 of Priest Patent No. 2,058,107,October 20, 1936) to first insert the slabbed-01f bolt shank through asquared aperture of the saw frame, and then, by a suitable flattening orpressing operation, to widen such slabbed-off shank portion; eitherthat, or to provide a blade-retaining member with a wide bearing surfaceand an unheaded shank portion, the latter being headed over afterinsertion through the squared aperture of the saw frame; in either case,the retaining member, by enlargement of one end or the other afterinsertion in the frame aperture, becomes an inseparable part of the sawframe. However, with a retaining member of the separable type hereindealt with, the bearing surface for the blade has always been relativelynarrow or limited in width, primarily because the width of surface 4,being the maximum cross sectional dimension of shank 2, was accepted asthe limit of stock width capable of passing through the saw framessquared socket or aperture, (marked 6 in Figs. 5 and 6), that receivesthe squared section 3. Our invention overcomes these difficulties byproviding a blade-retaining device made from the bolt or rivet of Fig.1, but having an effective bearing surface appreciably wider than thediameter of shank 2, thus minimizing the tendency of the saw blade totip or turn when in use; at the same time, the ability of the retainingdevice to pass through the squared aperture or socket 6 of the saw frameis fully preserved,

According to our invention, the material of shank 2, instead of beingslabbed off in the usual way as shown by Fig. 2, is subjected to aswaging, pressing and drawing operation, the effect of which, as bestillustrated by Figs. 3 and 4, is to transform or change the outer end ofsaid shank from a circular cross section to a substantially triangularcross section, the latter having two of its sides in fiat elongatedequal-width surfaces 1 and 8, Fig. 4, that stand substantially at rightangles to each other, and having its third side or hypotenuse in a thirdfiat surface 9, Fig. 3, which occupies a plane that substantiallybisects the squared section 3. This operation involves no cutting off ordiscarding of any of the stock of shank 2; although there is an excessof stock on account of the reduced thickness of the shanks cross sectionin this zone of flattening, a part of such excess is utilized along thelongitudinal edges of surface 9 in increasing the width of said surface,and the remainder of such excess stock is utilized in drawing up fromsaid surface 9 the integral projection III, for engagement with theusual hole in the end of the saw blade.

Although the surface 9, against which the saw blade bears, is thus givena width appreciably greater than in previous devices of this character,and appreciably in excess of the height or width of the square hole orsocket 6 of the saw frame, still this is no obstacle to the free passagethrough said hole or socket 6 of the blade retaining device of ourinvention; the reason for this being that the width of surface 9 doesnot exceed the diagonal dimension of said square hole or socket 6. Inconsequence, as shown in Fig. 6, to effect the insertion endwise of ourimproved blade-retaining device through the usual square hole or socket6 of the saw frame, said surface 9 is presented diagonally or cornerwiseto said hole, this being permitted by the companion fiat surfaces 1 and8 of the triangular cross section that coincide substantially with twoadjacent rightangle edges of said hole or socket 6; thereupon, theinward movement of the retaining device in this position is continueduntil the shanks round part II reaches the hole 6, at which time theshank is turned on its axis through to register the squared section 3thereof with the squared hole or socket 6 of the saw frame. The hole 6,as is usual in devices of this character, co operates with the squaredsection 3 of the device to prevent the latter from turning axially, whenoperatively associated with the saw frame. Thus our improved deviceaffords the usual opportunity for angular adjustment of the saw blade inthe frame, by retracting the squared section 3 from the aperture 6, andthen turning the device about its longitudinal axis to dispose thebearing surface 9 in either a horizontal or a vertical position, asdesired.

Our improved blade-retaining device affords definite economies inmanufacture over previous surfaces of previous blade-retaining devicesto forces tending to tip or turn said blade, or to disengage it fromsaid projection.

We claim:

In a hack saw, a frame, and a blade holder separable from said frame andcomprising a'shank having at one end an integral head and near the otherend a laterally projecting blade-engaging pin, said shank beingreceivable in a regular polygonal saw-frame aperture of more than threesides and of such size as to exclude said head,

and said shank adjacent said head comprising an intermediate reducedsection of a size smaller than said aperture and an end portion ofpolygonal cross-section fitting said aperture and preventing turning ofthe holder therein when said head abuts the frame, the shank portion inthe zone of said pin presenting a substantially fiat blade-contactingsurface from which said pin projects, and said surface having a width somuch greater than the shank diameter as to require its cornerwise pre- Fsentation to the saw-frame aperture, for passage of said shank portiontherethrough.

DWIGHT E. PRIEST. HARRY P. MACOMBER.

